Record cylinder carrier of speech recording or reproducing machines



Oct. 4, 1921.

w. GROENEBAUM RECORD CYLINDER CARRIER OF SI EECH RECORDING OR REPRODUCING MACHINES Filed March 5,

lawn/tar 5 7&w

arm 37:

.phonographs, and telephonographs.

Patented Oct. 4, 1927.

f U" T E WInirELMcRonNnBAU-M, OFNEU-BABELSBERG, nnaannnnm, GERMANY, Assmnoit TO. THE FIRM NAAMn-ooz-E vnnnoorscrmr nruzrncrnnnn MAAZTSGHAPPIJ BRIE-' R BERGEN, or sorrnvnmnenn; NETHERLAND$. a 2

nnconn' CYLINDER CARRIER or srnncn nnoonnmeon nnrsaonucrne. MACHINES.

Application filed March 5. 1925,5eria1. no.

This invention relates. to oa -method of manufacture anda construction of drum. for carrying the record cylinders of speech recording; or reproducing machines, such-as The drumsused hitherto are defective inasmuch as, they being necessarily of different inaterial from the recordcylinders, variations of temperature cause the record. cylindersv to, bind. upon the drums or to become loose.

As a rule, the drum is made-of metal, preferably aluminium, while the record. cylinder usually consistsofwax. The coefiiclents of expansion of thesematerials are very d ffen ent, so that if the record cylinder is put ou: at ordinary room temperature it will bind. if the temperature falls, and become loose if the temperature rises, thus interferin'g with the. use or operation of the ma- The'cause of this defect. is the lack chine. of resilience in the contacting parts, which do notyield sufliciently to allow for the difference in, expansion due to they temperature changes. Based on this discovery, the invention comprises adrum for carrying record cylinders, which has-yielding, resilient walls,

and-a surface of, particular -form,l which ensuresthatrecords can be put. on and taken off from and held firmly on the drum irrespective of changes of temperature. According, to. the'invention, a cylindrical or commonly a slightly coned hollow dr um is slottedlongitudinally to make its walls flexible,- and is somewhat swelled out in the. middle, i. e. made slightly barrel-sliaped,

by'a new method hereinafter described.

z-Theinventiorr is explained with reference to the accompanying drawing.

Figure 1 shows in longitudinal sectiona drum ready for subjection to the new method of manufacture; V

Figure 2 shows a section on of Figure 1. I

Figure 3 shows an axial section of a finished drum. 7

The drum is suitably formed of a hollow body 1 which may have 01' may be machined to have either a cylindrical or a slightly coned surface, to facilitate record cylinders being put on. End discs 232 are fastened upon the drum for mounting 1t, and on them are pivots 3 to be held in bearings. The surface of the bodyl is worked to near its final dimensions, and in the case of a the line 2 2 13,083, and in Germany January 28.1925:

allittle smaller than at the end.

yielding and. resilient narrow longitudinal I slots are cut in them. compression ring 6, WlllCll' may suitably be made in-twohalves with flanges 7 forbolting themtogether, is"

placed" around the body 1 in the groove 4.

The width of the ring 6 may suitably be equalto, and mustnot be greaterthanpthe width of the groove 4:. The inner'diameter of thering is somewhat less than thediam eter o'f the groove 4. l Vhen the flanges are drawn together .by tightening the bolts .8,

the walls of the body 1 are pressed inward to a determinedextentinthe middle. The

surface of the body. '1 isthen finished, the;

compression ring 6'not being in the way during this operationsince the surface does not need to be further worked whereitlis grooved. The surfaceis first turned to a cylindricalor slightly conical form, having however straight line generators, and to such a s ze. as adapts the external diameter of theends of the drum" to the internal dia meter of the record cylinderstobe mounted on it; while the remainder of the external; i i

surface of. the drumis fittedv to the. internal. measurements: of the cylinders which only have a spiral rib. on their in'nersurface. to

form. a seatingiupon the drum. -.ri'na'1iy the surface of the drum is polished...

When the compression.ringfiisiremoved,

in consequence ofthe. resilient walls offthe,

drum having been compressed during machining, the middle part of the surface swells out, as indicated in Figure 3.

this figure the broken line 9 indicates the 7 form prior to removal of the compression mug", and makes clear'the nature of the,

swelling. I I a When a record is pushed on to adrum so constructed, its wallsjcan yield resilientlyL The record is therefore held firmly in place.

If the temperature changes the walls'of the drum can yield becauseyof the slots 5, so that the record does not become fast on the drum, but can easily be removed or put on I at any temperature.

so circumferential groove 4 of suitable width 3 is turned. To make the .walls' 'of the drum a The groove tshould, in the firstinstance, jibe of such depth that the adjacent finished surface of the drum is preferably only of vslightly largerdiameter than the outer di ameter' of the drum at the groove; or at any rate so that said adjacent finished surface isinotof lesser diameter than the diameter at the. groove. That is to say; at thejend of c "the finishing operation," the portions of the 10 '7 outwardly beyond the bottom ofthe groove dru'm adjacent' to the groove should project 4 to a minimun extent, and inno' case should 'said portionsbe lessthan'flush with said bot tom of the groove. In other words, the

wall. of the drumshould be as thin as possl bile with respect to the groove 4, in orderthat Lthe desired elasticity may be developed in V shaped; Drums The invention is not confined to the method give flexibility and is made somewhat barrelmade according to the V7 method described above as a way 'of'c'arrying out the invention are-recognizable by the shallowgrovearoundthem approximately in" #themiddle, where; the compression ringhas rlb enl placed.

I l im:

Afcarrienfor the record cylinders of speech recording and reproducing mach nes,

comprising aliollow body having an outer surface of revolution generated by a line slightly bowed in a" direction away from the axis'ofrevolution, the'walls of said bodybe Ting slit longi udinally.

speech recording and reproducing machines,

of. the body tordi vide the latter into a plu ralit'y. of strips; the latter, curving outwardly intermediate their endsto Limpart an out ivardly'bulging'torm to saiddrum in its norcarrier V I speech recording and reproducing machines,

mal condition: e s v I for the record cylinders of of manufacture described, but comprises the formof drum itself; Its essential character isti'c i s-"thatl the surface of a cylindrical or i slightly 'coni'callbody is slit lengthwise tocomprising a slightly barrel-shaped body composed of resilient longitudinal strips and discs to which the opposite ends of said forrotation in bearings." 1-. I :A' carr er forthe record cylinders of speech recordlng and reproducing machines,

metal body having itsouter surface slightly barrel-shaped, having longitudinal slots ex-' tending over a part of its length, and having the thickness. of its walls taperingfrom an intermediate point ofthe body towards the oppos'iteends thereof. Y

5. A carrier for the record cylinders of vbody are secured, said discs being adapted l' comprising a substantiallycylindrical hollow 65 speech recording and reproducingmachines, comprismg a substantiallycylindrical'holp lowi metal body, 'having its outer. surface slightly barrel-shaped, having longitudinal slotsextending over part of its 'len'gth and terme'diate itsends. I g V 6. A methodof manufacturingrecordcarriers for sound recording and'reproducing machines, which consists in grooving 'a sub stantially cylindrical hollowzbodycircumferentially at about its middle, slottingsaid' 70 7 having a'shallow circumferential groove "in body longitudinally through a portion of its length, constricting said'body by means 01 a-band in the groove, and turning said body by a rectilinearly moving, tool while so constricted. a I r V.

7 A method of manufacturing record carriers for sound recording and reproducing machines, which consists in slotting a .sub-

st-antially cylindrical hollowbody lorigitu dinally, constricting saidbody circumferent ially' intermediate. its'ends, and machining I while so constricted;

said body by a rectilinearly moving tool rgn 8. A method of manufacturing record carriers "for sound recording and reproducing machines; which consists mgslotnng a'sub- .stantially cylindrical hollow body longitudin'ally, and machining said body to taper its outer surface from an intermediate'point to M Ward its oppositeends;

' 1 In testimony whereof have atfixedl my slgnature.

WILHELM GRGENEBAUM a 

